Right, my first thought was dodgy VBR files, but then I realized that when files have a missing VBR header, the 2.0 software just prevents them from doing FF/RW at all. So I discounted that idea.

Although I wonder...

If a song had a VBR header, but the header was somehow wrong, maybe the player would incorrectly interpret it and cause this "stuck" behavior. Dunno, I don't have any files with trashed VBR headers to test against.